One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,3,4)(7,11)(10,12)(14,18)(16,19)(20,25)(21,26)(22,28)(24,27)(6,9)(7,11)(13,14,19,26,17,21,16,18)(15,22,27,25,23,20,24,28)(2,4)(5,6)(7,10)(8,9)(11,12)(13,15)(14,20)(16,24)(17,23)(18,25)(19,27)(21,22)(26,28) involution — undirected(6,9)(10,12)(14,18)(15,23)(16,19)(20,28)(21,26)(22,25) involution — undirected(5,7,8,11)(6,10,9,12)(14,21)(15,23)(18,26)(24,27)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.